Image reading, processing and recording with quick data compression

Abstract

There is disclosed an image processing apparatus in which variable-length compression is performed, e.g. by orthogonally transforming input image data in units of frames, and quantizing the transformed image data. A quantization coefficient used in coding a last image on the basis of image data quantities of a plurality of frames which have been compressed, is controlled.

What is claimed is:  
     
       1. An image processing apparatus comprising: 
       a) compression means for performing variable-length data compression of input image data for n frames (where n is an integral number);  
       b) detecting means for detecting a difference between a prediction coded data quantity of the n frames and a sum of coded data amount of (n−1) frames which are actually coded; and  
       c) control means for controlling a compression state, for at least one frame of the n frames, of said compression means on the basis of a detection output of said detecting means, wherein, for n>2, each of the n−1 frames are coded on the basis of a result of coding the n-th frame without reference to any other frame.  
     
     
       2. An apparatus according to claim  1 , wherein said compression means includes: 
       conversion means for performing orthogonal transformation of the image data; and  
       means for quantizing the image data orthogonally transformed by said conversion means using variable quantization coefficients.  
     
     
       3. An apparatus according to claim  1 , further comprising: 
       storage means for storing the image data compressed by said compression means in a medium having a predetermined storage capacity.  
     
     
       4. An apparatus according to claim  1 , wherein said control means controls said compression means on the basis of a total of data quantities of the plurality of frames. 
     
     
       5. An apparatus according to claim  1 , wherein said compression means compresses a first frame at a relatively high compression ratio. 
     
     
       6. An apparatus according to claim  1 , wherein said control means controls said compression means on the basis of the image data of the plurality of frames compressed by said compression means when image data of the last frame of the series of the plurality of frames is compressed. 
     
     
       7. An image processing apparatus comprising: 
       a) compression means for performing variable-length data compression of input image data for n frames (n is an integral number);  
       b) recording means for recording the image data compressed by said compression means in a recording medium;  
       c) memory means for memorizing a first frame of the n frames; and  
       d) control means for controlling coding for the first frame on the basis of a difference between a prediction coded data quantity of the n frames and a sum of coded data amount for a second frame to n-th frame of the n frames, the amount representing an actual code length of coded data, wherein, for n>2, each of the n−1 frames are coded on the basis of a result of coding the n-th frame without reference to any other frame.  
     
     
       8. An apparatus according to claim  7 , wherein said compression means includes: 
       conversion means for performing orthogonal transformation of the image data; and  
       means for quantizing the image data orthogonally transformed by said conversion means using variable quantization coefficients.  
     
     
       9. An apparatus according to claim  7 , wherein said control means controls to compress the first frame of image data held in the medium, and to record the compressed data in the recording medium. 
     
     
       10. An apparatus according to claim  7 , wherein said compression means is means for compressing the second and subsequent frames of image data on the basis of a result of compressing the first frame of image data. 
     
     
       11. An apparatus according to claim  7 , further comprising: 
       generation means for generating the image data in units of frames.  
     
     
       12. An apparatus according to claim  11 , wherein said generation means includes means for photoelectrically converting an image. 
     
     
       13. An apparatus according to claim  7 , wherein said control means causes said compression means to compress the second and subsequent frames of image data, and determines a compression ratio of the first frame of image data in accordance with quantities of the compressed image data when the plurality of frames of image data are continuously recorded.